There is a color erasing apparatus that erases a color of an image on a sheet subjected to image formation. The color erasing apparatus includes a color erasing section configured to apply heating processing to a sheet on which an image is formed with an erasable color material and erase a color of the image (the color material) on the sheet. The color erasing apparatus includes a reading section configured to read the image on the surface of the sheet. The color erasing apparatus determines, on the basis of the image read by the reading section, whether the sheet to be subjected to color erasing processing is color-erasable or whether the color erasing processing is successful.
The color erasing section of the color erasing apparatus erases a color of an image on the sheet by heating a conveyed sheet. In order for the color erasing section to surely perform the color erasing, the sheet conveyed through the color erasing section needs to be conveyed at appropriate conveying speed. On the other hand, in order for the reading section to surely read the image on the sheet, the sheet needs to be conveyed through the reading section at appropriate conveying speed. The conveying speed of the sheet passing through the color erasing section during the color erasing processing (hereinafter referred to as color erasing speed) and the conveying speed of the sheet passing through the reading section during reading processing or sorting processing (hereinafter referred to as reading speed) respectively depend on the performance of the color erasing section and the performance of the reading section. For example, the reading section could read the image on the sheet at the reading speed higher than the color erasing speed of the color erasing section. However, when a reduction in size of a conveying path is examined, the color erasing apparatus needs to convey the sheet to the reading section at the color erasing speed lower than the reading speed. In other words, the conveying speed of the sheet in the color erasing apparatus is controlled according to the lower conveying speed. Therefore, the performance of processing of the entire color erasing apparatus falls.
Therefore, there is a demand for a color erasing apparatus that can realize a reduction in size and improve processing performance.